Windows Event Application logs get frequent information level entries, logs may become flooded under certain unclear circumstances, which can hinder work.
In essence the issue should have little to no impact on performance/usability.
Login failed for user 'IIS APPPOOL\Classic .NET AppPool'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: <local machine>]
Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. [CLIENT: <local machine>]
This issue is a minor configurational issue with IIS 7.5. No functionality loss is expected.
This seems to be an issue with how application pool Identities are passed to SQL Server.
There are few things that can be done about this:
1. Apply Hotfix from Microsoft http://support.microsoft.com/kb/2545850
2. Refer to KB TECH160815 and change Application pool identity to "LocalSystem" value from "ApplicationPoolIdentity".
You can refer to this article for steps on how to change/set application pool
SMP 7.1.1 ; 7.1.2